The Coral Red Pencilfish (Nannostomus mortenthaleri) is a small, peaceful, and strikingly colored freshwater fish native to slow-moving streams and blackwater habitats in South America. Ideal for nano or planted aquariums, they thrive in soft, acidic water with gentle filtration, subdued lighting, and plenty of plants or floating vegetation to mimic their natural environment. These schooling fish should be kept in groups of at least 6 to encourage natural behavior and reduce stress. They are omnivorous, feeding on high-quality micro-pellets, finely crushed flakes, live or frozen foods like daphnia and brine shrimp, and small amounts of vegetable matter. Coral Red Pencilfish are delicate and sensitive to water quality, so frequent water changes and stable parameters are essential. When properly cared for, they display vibrant coloration and can live several years as part of a peaceful community tank.
| Parameter | Requirement |
|---|---|
| Scientific Name | Nannostomus mortenthaleri (Coral Red Pencilfish) |
| Tank Size | Minimum 10 gallons |
| Temperature | 24–28°C (75–82°F) |
| pH Range | 5.5–7.0 |
| Water Hardness | Soft (1–8 dGH) |
| Substrate | Sand or fine gravel with dense plants and floating vegetation |
| Diet | Omnivorous – micro-pellets, finely crushed flakes, live/frozen daphnia, brine shrimp, small amounts of plant matter |
| Temperament | Peaceful, ideal for community tanks |
| Social Behavior | Schooling; best kept in groups of 6+ |
| Breeding | Egg scatterer; small floating plants help fry survival |
| Lifespan | 3–5 years with proper care |
